This invention relates generally to an orthosis for passive or active movement of a joint and more particularly concerns a therapeutic apparatus which will enable exercising of a body joint and the muscles of the surrounding limb without direct application of pressure on that joint. The invention is particularly effective for a joint such as an elbow joint.
An orthosis is an orthopedic instrument that applies motion to a part of a body. After injury or illness or following surgery or other medical techniques affecting a limb of the body, the joint may stiffen very rapidly as a result of its immobilization, and, in such a case, usually requires a great deal of therapy to enable that joint to regain its motion. The therapy involved may take two forms. It may be necessary to move the joint, under controlled conditions as prescribed by an attending physician, where the patient has not sufficient muscle development to flex and extend the parts of the limb about that joint. In such a case it is necessary to apply external force to flex and extend the body portion surrounding the joint, for example with the aid of a physical therapist who carefully moves the limb, flexing it and extending it about the joint to induce motion. Such externally induced motion is called "passive motion". The second form occurs when the patient has or has developed sufficient muscle strength in the body portion surrounding the joint to himself flex or extend the limb, although the muscle strength may be much reduced and motion may be extremely slow and painful. Such motion will be called "active motion". In situations where either passive or active motion is involved, the range of extension and flexion motion of the parts of the limb about the joint may, as a result of the patient's condition, be greatly reduced from normal. This range of motion, measured in degrees, for the parts of an arm about an elbow, may range from zero degrees to 130 degrees for a normal, healthy arm. After injury, surgery or illness, for example, this range may be greatly restricted, for example to 50 degrees to 85 degrees (extension to flexion).
The procedures requiring motion of a body joint traditionally often require care by a physiotherapist, and occupy substantial time, effort and attention with each patient. In addition, such treatment may be frequently painful to the patient and too irregular for maximum benefit.
Devices have been proposed previously which will assist a physiotherapist to exercise a disabled joint of a patient or which will assist the patient himself to administer the manipulative treatment himself. For example, U.S. Pat. No. 2,832,334 of Whitelaw, issued Apr. 29, 1958, describes a therapeutic device consisting of two bars joined at a pivot, the device to be strapped to the limb having the joint to be exercised so that the pivot of the device is positioned adjacent the joint to be manipulated. Associated with the pivot is a housing containing gear and pinion members which cooperate with a friction member to enable adjustment of the resistive forces acting against the pivoting of the bars or alternatively to adjust the amount of external force which is applied to the device to enable motion to be imparted to the bars and the joint. This device requires careful machining of the components to be fitted into this housing, as well as relatively detailed assemblage thereof, and consequently is a relatively expensive device. In addition, this device does not give adequate support of the limbs of the body to enable it to be used for a badly damaged joint where, for example, there may be lateral drift to the joint.
Keropian, U.S. Pat. No. 2,767,708, issued Oct. 23, 1956, describes and illustrates an orthopedic brace for a hand which is secured to the forearm. The device comprises a hand support made up of a pair of spaced, articulated bars disposed on the inner and outer side of the forearm and hand. The device however is not intended or designed for exercise or movement of limb joints, its purpose being mainly to urge the hand of the wearer towards an open or closed position.
Other references describing joint manipulating or exercising apparatus are U.S. Pat. No. 3,976,057 of Barclay, issued Aug. 24, 1976; U.S. Pat. No. 3,683,897 of Shield, et. al., issued Aug. 15, 1972; and U.S. Pat. No. 3,323,518 of Swanson, issued June 6, 1967;--all of which describe relatively complicated mechanical means to enable or cause pivoting of braces strapped to limbs about the joint region.
Also of background interest is U.S. Pat. No. 3,785,371 of Lewis, issued Jan. 15, 1974 which describes and illustrates an elbow sleeve for restricting an elbow against straightening beyond a preselected adjustably variable bent position.
Other types of braces of general background interest are illustrated in Canadian Pat. No. 519,118, issued Dec. 6, 1955 to Seelert and Canadian Pat. No. 595,450, issued Apr. 5, 1960 to Rehnberg.
It is an object of the present invention to provide an inexpensive, lightweight, portable therapeutic device which may be used to impart passive or active motion to the limbs surrounding a joint of a body such as the elbow joint or knee joint. It is a further object of the device to provide a simple device which may be operated by the patient himself or a physiotherapist, to impart both flexing and extending motion to such limbs or to so exercise them to increase muscle strength and to increase the range of motion of the limbs. It is a further object of the present invention to provide a device of the type described which will enable the operator to impart the desired motion to the joint by the application of controlled, predetermined forces. These and other objects of the invention will be understood from the following description of the invention.